卵 is the scientific/biological term for egg —
产卵 (chǎnluǎn, 'to lay eggs') is for animals,
卵巢 (luǎncháo, 'ovary') is medical. For everyday food eggs, use
蛋 (dàn):
鸡蛋 (jīdàn, 'chicken egg'), not
鸡卵. In some dialects,
卵 is slang for testicles — be aware of this in informal contexts.
